The infected systems were joined together in a botnet that researchers from cybercrime intelligence firm IntelCrawler dubbed Nemanja. The researchers believe the attackers behind the operation might be from Serbia.

The size of the botnet and the worldwide distribution of infected systems brings into perspective the security problems faced by retailers from around the world, problems that were also highlighted by the recent PoS breaches at several large U.S. retailers.

Past incidents suggest an increased attention from cybercriminals toward retailers and small businesses that use PoS terminals, the IntelCrawler researchers said Thursday in a blog post. "We predict an increasing number of new data breaches in both sectors in the next few years, as well as the appearance of new types of specific malicious code targeted at retailers' backoffice systems and cash registers."

According to IntelCrawler, the Nemanja botnet included 1,478 infected systems in countries on most continents including the U.S., the U.K., Canada, Australia, China, Russia, Brazil and Mexico.

An analysis of the Nemanja botnet revealed that the compromised systems were running a wide variety of PoS, grocery store management and accounting software that is popular in different countries. The IntelCrawler researchers identified at least 25 different such software programs used on those systems.

This doesn't mean that the identified applications are particularly vulnerable or insecure for further use, but shows that the Nemanja PoS malware was designed to work with different software. Despite the ability to collect credit card data, the malware also had keylogging functionality to intercept credentials that could provide access to other systems and databases that contained payment or personally identifiable information.

IntelCrawler predicts that very soon modern PoS malware will be incorporated as modules into malicious remote access tools (RATs) or other Trojan programs and will be used along other components, like those for keylogging or network traffic sniffing.

Security firm Trustwave recently said in a report that one in three data breaches the company investigated last year involved compromised PoS terminals. A separate report from Verizon released in April and based on a larger data breach caseload revealed that PoS intrusions was a factor in 14 percent of confirmed data breaches.

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